Prior art RF excited gas laser design pioneered by Katherine D. Laakmann (U.S. Pat. No. 4,169,251) defines an elongated laser resonator chamber being excited by transversely applied radio frequency (RF) field.
This basic design of RF excited laser has been further improved by Peter Laakmann (U.S. Pat. No. 4,805,182) through all-metal laser tube arrangement having metal electrodes and metal side-walls forming an elongated laser resonator chamber with electrodes and side-walls being diffusion-cooled by closely spaced walls of the metal tube envelope. Square shaped elongated laser tube is placed inside of the laser housing assembly in such a way that only two (opposite) sides of the tube could be cooled by the heat-sinking walls of the laser housing. These heat-sinks, i.e. the walls of the housing, are cooled by forced air flow or by liquid coolant. At least one side surface of the laser tube faces the heat dissipating power supply electronics compartment, which limits cooling efficiency of the laser tube and is a disadvantage of this design. In order to prevent laser tube from thermal distortions, it needs to be thermally isolated from electronics compartment, which further complicates laser design.
The art of the forced air cooled RF excited gas lasers is further advanced by Yefim Sukhman et. al. (U.S. Pat. Nos. 5,754,575 and 5,894,493) through flexible tube-to-heatsink interface minimizing laser tube deformations induced by the heat-sinks. A disadvantage of all prior art designs is in the complexity of the flexible tube-to-heat interface assemblies. Another disadvantage of this design is in relative inefficiency of the laser tube cooling because of the close proximity of heat dissipating power supply compartment. Furthermore, only 50% of the laser tube surface can be cooled, which also contributes to low cooling efficiency of this design. Another disadvantage of this design is in relatively inefficient cooling of the power supply electronics, which is mounted onto the heat spreader in close proximity of the heat dissipating laser tube.
Forced air cooling concept in RF excited gas lasers was modified by Yefim Sukhman et. al. (U.S. Pat. No. 5,901,167) through defining separate air flow passages for laser tube and for power supply housing. A disadvantage of this design is in high air flow resistance resulted from the complexity of the air duct geometry. Increased air flow resistance results in reduced air flow if inexpensive and convenient axial fans are used. Reduced air flow limits cooling efficiency. An additional disadvantage of this and other prior art designs described above is in the relative complexity and cost of the laser housing.
It is an object of the present invention to reduce the cost and to simplify the forced air cooling design in gas lasers with RF excitation. It is a further object of the current invention to improve and simplify the cooling of laser tube internal electrode structure.